Is there enough renewable energy to maintain our consumptive lifestyle?

A common argument against switching to renewable sources of energy is that the supply is insufficient to meet world energy needs.  Current world energy consumption is a little less than 20 Terawatts (TW) per year (= 20 X 10¹² watts).  Much of that energy is wasted, so with an emphasis on efficiency and conservation, that 20 TW figure need not increase in the near future.

Are there renewable energy sources equal to 20 TW per year? The breakdown is as follows; geothermal is about 70TW, ocean energy about 200TW, wind about 370 TW, and solar about 89,000 TW. In other words, a total of around 89,640 TW. Of course most of the solar and wind resources are over the oceans and therefore not readily available for conversion to a useable form of energy. A more realistic estimate of the available renewable resources would be around 25,000 TW. Of that 25,000 TW, we only need to utilize 20 TW to supply the energy demands of the entire human race! In other words, the renewable supply is about 1200 times the yearly world energy demand, and will continue to be so forever (in human terms anyway).

How does the renewable supply of energy compare to the supply available from fossil fuels and nuclear fuels? The estimated in-the-ground reserve of fossil fuel is about 9,000 TW and nuclear fuel is about 59,000 TW. That means that the amount of solar energy hitting the earth each year exceeds all known reserves of the non-renewable sources of energy.

Jack Pickett Sr. Warden